luya\cms\menu\Item: getPrevSibling() and getNextSibling() do not sort by sortIndex

[rolandschaub]

luya-module-cms/src/menu/Item.php

Line 558 in ce73c6e

public function getNextSibling()

getPrevSibling() and getNextSibling() return one menu item that has a smaller (prev) or higher (next) sortIndex than the current menu item. This doesn't always work correctly as the query is not sorting the menu items by SortIndex.

[nadar]

There is an orderBy method which could be added (https://github.com/luyadev/luya-module-cms/blob/master/src/menu/Query.php#L318-L330) would you like to send a PR?